The present invention relates to a positive shut off to the flow of water into the tank of a toilet (water closet) of the kind normally found throughout the world.
Toilet systems, as used in the American home, have been connected to the potable water supply. The average American home has from one to three of these toilets, each of which uses approximately 3.5 gallons, or more, of water per flush. The majority of these toilets operate by means of a flotation device attached to a water flow valve. When the toilet is flushed, a chain connected to the flush handle lifts a stopper opening an outlet in the bottom of the toilet tank. The water from the tank flows into the toilet bowl raising the level of water therein. When the water in the toilet bowl exceeds the height of the bowl drain, water begins to flow from the bowl by a siphoning effect which suctions out all water and waste in the toilet bowl. During this period of time, the flotation device, floating on the water in the tank, drops as the tank water level drops thereby opening a water inlet valve. When all water has exited the tank, the stopper falls closing the open outlet. The water now entering the tank, through the inlet valve, fills the tank. As the water level rises the float rises until the water valve is closed.
This system is effective, simple and relatively efficient. However, it can also be extremely wasteful. Should the stopper that closes the tank outlet wear, or become distorted, a leak occurs that allows water to constantly flow into the toilet bowl. Should enough water escape the tank, the float drops opening the water inlet valve to replace the lost tank water. Conversely, the inlet valve is subject to distortion and/or the buildup of minerals, particularly in hard water areas, that interfere with its efficient operation to the point where it will never completely close. The same result may occur from improper adjustment of the flotation device. In these latter cases, there is a constant flow, however small, of water into the tank. To preclude flooding, an overflow tube in the tank exits the excess water into the toilet bowl. Thus, the level of water in the tank never exceeds the height of the overflow tube, given the current designs, as the amount of water that may be introduced into the tank at any given time is less than the amount of water that the overflow tube permits to escape. However, this continual flow also leads to a waste of water.
Potable water, or fresh water, and its availability is becoming a significant environmental concern. Changing weather patterns, increased agricultural needs, the cutting of woods and forests, and the increasing destruction of water sheds have reduced the quantity of fresh water available. These factors, combined with population growth, have created severe strains on the ability of both nature and man to supply the necessary potable water. It is not uncommon to hear about local water rationing during peak water use periods. The problem has become so severe in some areas that legislatures, such as Massachusetts and California, have now legislated the use of toilets using less than the standard 3.5 gallons of water.
This problem has been addressed, principally in the context of public toilets, that is, toilets in public facilities that normally do not have toilet tanks but rather have metered flush valves or other mechanical or electrical shut-off devices in the water line.
However, a fluid operated valve for use with a toilet tank was disclosed in U.S. Pat. No. 1,145,791 issued to L. F. Pigott on July 6, 1915. The patent disclosed a tank inlet valve assembly comprising an impeller screw seated in an inlet housing. The impeller is connected by a shaft to a screw, intermeshing with the screw is a second screw which is connected by a rod to a valve. The valve closes an outlet port. Attached to the second screw, at the side opposite the valve, is a spring that is under tension when the valve is closed. The valve is activated by pulling a flush handle. The flush handle rotates an arm that supports the rod having the valve on one end and the screw with spring assembly on the other. This rotation disengages the two screws allowing the spring to retract, pulling the second screw, rod and valve assembly rearwardly to open the outlet port. When the flush handle is released, the rod is pulled back into position by a spring, remeshing the first and second screws. As the valve is opened, fluid exits through the outlet port thereby allowing water to enter through the inlet port, turning the impeller which in turn drives the first screw, now intermeshed with the second screw, until the valve is closed.
U.S. Pat. Nos. 1,552,261; 1,809,440 and 4,624,444, of Belcher, Elder and Johnson respectively, disclose metered flush valves that eliminate the need for a tank and are normally found in public facilities. The patent of Belcher, No. 1,552,261, discloses a metering device consisting of a valve that opens into the water flow and is closed by a combination of a spring pressure and water pressure. When the flush handle is turned, a mechanical linkage forces the valve open and locks it open by means of a ratchet. Water then flows through an impeller that is linked by a series of gears to a bar mechanism that is raised by the rotating impeller. The bar strikes the retaining ratchet tooth disengaging it and allowing the valve to close.
U.S. Pat. No. 1,809,440, of Elder, also discloses a valve for controlling the flow of water by turning off the water after a predetermined time or a given amount of water has passed. When the flush handle is rotated, paired inlet valves are opened to permit the water to flow. The flowing water strikes a turbine wheel. The turbine wheel is connected by a series of gears to a spiral gear that moves an arm to cause the rotation of the valves to a closed position. The patent of Johnson No. 4,624,444, is representative of shutoffs for flush toilets used in commercial establishments having pressurized lines.
Water control meters are also known for use in controlling watering devices. U.S. Pat. Nos. 4,280,530, of Yi, and 4,708,264, of Brunninga, are devices of this type. The device of Yi is placed in the water line for dispensing water to sprinklers or agricultural irrigation systems. Water enters through an inlet into an impeller chamber. The speed of rotation of the impeller is controlled by speed adjusting means which is essentially a frictional contact. The water flows from the impeller chamber into a second chamber containing the outlet valve. The outlet valve is set on one of three preset positions. Thus, the flowing water causes the impeller to rotate and an attached pinion gear initiates a gear train that terminates in a crescent gear. The crescent gear acts as a timing gear linked to the outlet valve and as it rotates, it slowly closes the valve to stop the flow of water. Pat. No. 4,708,264, the device of Brunninga, also discloses a timed water meter for a hose or sprinkling system. The outlet valve is set to a predetermined open position and water flowing through the system rotates an impeller which is linked through a series of planetary gears to rotate the valve control assembly. The valve control assembly rotates until released, at which time it permits the valve to be closed.
An electronic water controller is disclosed in U.S. Pat. No. 4,633,905 of Wang. As water flows over a water wheel, magnetic sensors within the wheel cross a relay thereby inputting the flow rate into a microprocessor. On the basis of the flow rate and the amount of water to be dispensed, the microprocessor computes the time that the outlet valve should be open. The outlet valve is opened by rotating a cam which in turn raises a post attached to the outlet valve. The outlet valve remains open until the calculated flow time has been achieved at which time the motor rotates the cam to a point where the post is allowed to fall and the valve closed. The valve itself is forced into a closed position by a spring.
Another device for measuring a precise amount of water is that of Johns, U.S. Pat. No. 1,407,752. This is an in line measuring device that uses a combination of gearing and pressure differential associated with a piston to control the flow of water.
U.S. Pat. No. 4,335,852, of Chow, discloses another device for controlling the flow of fluid. The device consists of a flow inlet having a valve placed therein. The valve has an associated stem that is positioned to ride on a cam. The device is pre-set for a given amount of flow. When the water flow is initiated it flows by an impeller which is connected by means of intermeshing gears to an eccentric shaft that drives a pawl and rachet, the rachet being attached to the cam. The rachet rotates the cam until such time as the stem can be pushed back into the stem notch. In addition to relying on water pressure to close the valve, a spring is placed between the ferrule cup, in the inlet, and a stud in the center of the valve assembly. The sealing means is an O-ring, around the valve, that is slightly larger than the opening for the inlet valve.